[PATCH] PM / wakeup: Add device_children_wakeup_capable()

[Matthias Kaehlcke]

Add device_children_wakeup_capable() which checks whether the device itself
or one if its descendants is wakeup capable.

Change-Id: Ib359eb5ac8650ddf9889c7d1f77707f50777fe99
Suggested-by: Felipe Balbi <balbi@xxxxxxxxxx>
Signed-off-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
---
 drivers/base/power/wakeup.c | 17 +++++++++++++++++
 include/linux/pm_wakeup.h   |  6 ++++++
 2 files changed, 23 insertions(+)

diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
index 9c0932603642..2aee7fa8230f 100644
--- a/drivers/base/power/wakeup.c
+++ b/drivers/base/power/wakeup.c
@@ -483,6 +483,23 @@ int device_set_wakeup_enable(struct device *dev, bool enable)
 }
 EXPORT_SYMBOL_GPL(device_set_wakeup_enable);
 
+static int __device_children_wakeup_capable(struct device *dev, void *dummy)
+{
+	return device_may_wakeup(dev) ||
+		device_for_each_child(dev, NULL, __device_children_wakeup_capable);
+}
+
+/**
+ * device_children_wakeup_capable - Check whether a device or one of its descendants is
+ *                                  wakeup capable.
+ * @dev: Device to handle.
+ */
+bool device_children_wakeup_capable(struct device *dev)
+{
+	return __device_children_wakeup_capable(dev, NULL);
+}
+EXPORT_SYMBOL_GPL(device_children_wakeup_capable);
+
 /**
  * wakeup_source_not_registered - validate the given wakeup source.
  * @ws: Wakeup source to be validated.
diff --git a/include/linux/pm_wakeup.h b/include/linux/pm_wakeup.h
index 661efa029c96..a0ca42aac6d6 100644
--- a/include/linux/pm_wakeup.h
+++ b/include/linux/pm_wakeup.h
@@ -97,6 +97,7 @@ extern int device_wakeup_disable(struct device *dev);
 extern void device_set_wakeup_capable(struct device *dev, bool capable);
 extern int device_init_wakeup(struct device *dev, bool val);
 extern int device_set_wakeup_enable(struct device *dev, bool enable);
+extern bool device_children_wakeup_capable(struct device *dev);
 extern void __pm_stay_awake(struct wakeup_source *ws);
 extern void pm_stay_awake(struct device *dev);
 extern void __pm_relax(struct wakeup_source *ws);
@@ -167,6 +168,11 @@ static inline bool device_may_wakeup(struct device *dev)
 
 static inline void device_set_wakeup_path(struct device *dev) {}
 
+static inline bool device_children_wakeup_capable(struct device *dev)
+{
+	return false;
+}
+
 static inline void __pm_stay_awake(struct wakeup_source *ws) {}
 
 static inline void pm_stay_awake(struct device *dev) {}